This invention is directed to a slider suspension system for a semi-trailer. A slider frame can be moved forwardly or rearwardly in relation to the tractor rear axles in order to maximize the load carrying capacity of the semi-trailer while complying with roadway weight laws.
A slider frame is usually sold with suspension hangers attached thereto, but can be sold without these hangers. When put in use, two axles are connected by means of springs and torque arms to the suspension hangers and the slider frame is attached to two elongated body rails which are welded to the underside of the trailer by means of a locking mechanism using cylindrical pins which positively attach the slider frame to pin receiving holes in the body rails.
The conventional slider frame assembly of the past has been constructed using two longitudinal G-channel side rails, three to five C-channel cross-members and many doublers, gussets, and cross-braces. The design of the frame with the conventional G-channel side rails provides a strong rigid connection to the tops of the suspension hangers which are attached to these channels. However, the G-channel side rails are relatively heavy and because of their shape trap road grime. Thus, their use causes both a weight penalty and corrosion problems. The use of C-channel cross-members is unsatisfactory because they are effectively rigid in only the direction dependent upon their orientation and geometry and are sensitive to the manner in which they are welded to the side rails. These welds often develop cracks and to correct the cracks specific welding techniques must be used and gussets and stiffeners must be installed thereby increasing the weight of the slider frame.
Accordingly, it is an object of this invention to provide a slider frame which is lighter yet stronger than present slider frames while using C-channel side rails which will not trap road grime.
Another object of this invention is a slider frame which uses tubular cross-members which can effectively translate loads in all directions and are torsionally rigid.
Another object of this invention is a slider frame utilizing C-channel side rails which are locally reinforced above each suspension hanger and provide a clean tie in between the side rails, suspension hangers and cross members.
Another object of this invention is a reinforcing pan for a suspension hanger which also mounts a tubular cross-member and rigidly connects it tied the side rails.
Another object of this invention is a slider frame which utilizes lightweight C-channel side rails by providing pan shaped box type reinforcing members at the suspension hangers.
Another object of this invention is a slider frame having C-channel side raises which have openings to receive tubular cross-members.
Other objects may be found in the following specification, claims and drawings.